Golden State Warriors star Draymond Green is apparently still catching flak for his “greatest defender in NBA history” comment, this time from a basketball titan in Boston Celtics legend Bill Russell.

Russell hilariously subtweeted Green (at least we'd like to think so) by joking teams were calling him to come out of retirement and make his presence felt. The tweet even came equipped with a video of Russell lifting a kettlebell.

The Hall of Famer made sure to tack on the obligatory #AprilFools reference:

Green had choice words regarding his place among the greatest defenders in NBA history. His comments garnered plenty of backlash, even from former NBA veterans like Tony Allen and Baron Davis.

But there is no doubt whatsoever as to Bill Russell's status as one of the best defenders in the history of the game.

The five-time league MVP led the league in Defensive Win Shares in 11 different seasons. His 133.64 Defensive Win Shares mark for his career dwarfs all others in NBA history. Former San Antonio Spurs great Tim Duncan is second on that list with 106.34 DWS.

Russell was one of the only guys who even remotely had success against Wilt Chamberlain, and their frequent clashes helped establish one of the first and greatest individual rivalries in NBA history.

The 87-year-old is still revered by NBA personnel. He also has remained quite visible and active on social media. Russell's even got jokes, apparently.

Draymond Green is always likely to spark quite a bit of dialogue as someone who is never afraid to speak his mind. But Bill Russell is not afraid to speak his mind or have some fun, either. Beware of the clap back.